A deadly outbreak of suspected hantavirus on a Dutch cruise ship off West Africa this month has highlighted the ease with which diseases spread on cruises. Three passengers have died and three others are receiving care, though only three hantavirus cases have been confirmed. While such outbreaks are rare, experts caution that larger cruises with thousands of passengers create ideal conditions for transmitting more common illnesses.
Norovirus is the most frequent cause of cruise outbreaks, responsible for 90% of diarrhoeal disease cases on board. Data from the US Centers for Disease Control and Prevention shows it caused 18 of last year's outbreaks, the highest number in 12 years. The virus spreads via contaminated food, water, or surfaces and can survive for weeks, resisting many disinfectants. Hand washing with soap and water is recommended over hand sanitiser.
Legionnaires' disease, a severe pneumonia caused by Legionella bacteria, was diagnosed in two passengers after a Norwegian cruise last year. Although most people exposed do not fall ill, one in ten cases can be fatal. The bacteria spreads through mist from baths, pools, hot tubs, and showers, but not person to person. No vaccine exists, and treatment requires hospital care with antibiotics or oxygen.
COVID-19 and flu remain concerns on cruise ships. COVID spreads via infected droplets and surfaces, and while caseloads have fallen, infections still kill dozens weekly in the US. The flu season has been severe in recent years, partly due to vaccine hesitancy. Experts advise that crowded indoor spaces are still risky for transmission.
